1. Field of the Invention
The present invention relates to circuitry for video players. More specifically, a single chip electronic circuit is disclosed. The single chip electronic circuit comprises a digital video disk read-only-memory (DVD-ROM) controller circuit and a Moving Picture Experts Group (MPEG) decoder circuit. The former performs servo control and Error Correction Code (ECC) coding while the latter performs audio and video decoding, and both circuits utilize the same memory controller.
2. Description of the Prior Art
Because of its significantly improved video and audio qualities, the digital video disk (DVD) standard has begun to make significant headway into the entertainment market, and is beginning to displace the traditional videocassette tape formats, such as vertical helix scan (VHS), or the traditional audio and video format encoded on a CD-ROM disk, such as video compact disk (VCD). To be more compatible with the old system, most DVD players are capable of reading both DVD disks and VCD disks. Therefore, more and more users are buying DVD players to replace, or at least augment, their older VHS or VCD equipment. This benefits the industry, as a new market is forming and many products are needed. Consumers also benefit as DVDs require less storage space, offer higher video and audio resolutions, and furthermore are capable of offering a host of flexible settings and options that are simply unavailable under the old VHS or VCD systems. Perhaps the only drawback to the new DVD standard is that the typical consumer, having already invested in an older system, is unwilling to spend additional sums of money to upgrade to the newer DVD technology, despite all the inherit benefits of doing so. Consequently, it is desirable to bring down the cost of a DVD player to lower the financial barrier for such consumers.
Please refer to FIG. 1. FIG. 1 is a block diagram of a typical prior art DVD player 10. The DVD player 10 provides an audio signal to an audio device 8, and a video signal to a display device 9. The audio device 8 may be, for example, a home stereo system, and the display device 9 may be a television set. Alternatively, the DVD player 10 may be part of a handheld system that includes a liquid crystal display (LCD) as the display device 9, and one or more speakers (or an audio output jack for headphones) as the audio device 8. The DVD player 10 generates the audio and video signals by reading a DVD disk or a VCD disk, and has a disk drive loader 12 that-is capable of reading such types of disks. That is, the disk drive loader 12 can read both DVD disks and VCD disks. To be noted, in advanced designs, the disks need not be read-only in nature, i.e., ROMs, but could also be writable-type disks as well, such as CD-R disks, CD-RW, DVD+RW disks, etc. The disk drive loader 12 includes a platter mechanism 12a for loading and unloading the disks, a spindle motor 12b to provide the appropriate rotational velocity to such disks, and a pick-up head 12c to read digital data that is optically encoded on the disks.
A DVD-ROM controller 20 is provided within the DVD player 10 to control the disk drive loader 12 and to decode the data read from the disk drive loader 12. In particular, the data stored on the disks is encoded in a special manner to provide for error correction coding (ECC), and it is necessary to perform an ECC decoding process upon this encoded data so as to extract the decoded data that is intended for use. The decoding method used will depend upon the type of disk being read within the disk drive loader 12. The DVD-ROM controller 20 includes a servo control and ECC decoder 22, an IDE or A/V bus interface circuit 24, and a memory controller 26. The servo control and ECC decoder 22 controls the disk drive loader 12 to extract encoded data from a disk held within the platter mechanism 12a by controlling the spindle motor 12b and pick-up head 12c. The servo control and ECC decoder 22 utilizes the memory controller 26 to save the ECC encoded data streaming from the disk drive loader 12 into drive random access memory (RAM) 16 as ECC encoded data 16a. The memory controller 26 provides a memory interface for the disk drive loader 12 and servo control and ECC decoder 22 to read from and write to the drive RAM 16. The drive RAM 16 can be, for example, dynamic RAM (DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), etc. The servo control and ECC decoder 22 utilizes the memory controller 26 to then read ECC encoded data 16a from the drive RAM 16 and convert the ECC encoded data 16a into ECC decoded data 16b that is also stored within the drive RAM 16.
The bus interface 24 permits the DVD-ROM controller 20 to communicate with a bus 14 within the DVD player 10, and hence with a Moving Picture Experts Group (MPEG) decoder 30. The bus interface 24 is typically designed to interface with an Integrated Drive Electronics (IDE) bus, or any proprietary audio/video (A/V) bus. The MPEG decoder 30 has a similar bus interface 34, as the MPEG decoder 30 is also usually a single integrated chip. When a block (typically a sector) of newly decoded data 16b has become available in the drive RAM 16, the DVD-ROM controller 20 utilizes the bus interface 24 to signal the availability of the newly decoded data 16b to the MPEG decoder 30. The MPEG decoder 30 then utilizes its bus interface 34 to request and receive the decoded data 16b from the DVD-ROM controller 20 and store it in graphics RAM 18 as graphics data 18a. Depending upon the graphics data 18a, an MPEG processor 32 within the MPEG decoder 30 is capable of performing an MPEG type-1 or an MPEG type-2 decoding process on the graphics data 18a to generate audio data 18b and video data 18c. The audio data 18b and video data 18c are then respectively streamed by the MPEG decoder 30 to the audio device 8 and display 9. As with the DVD-ROM controller 20, the MPEG decoder 30 has a memory controller 36 that permits the MPEG decoder 30 to read from and write to the graphics RAM 18, which is external to the MPEG decoder chip 30.
The prior art DVD player 10 requires two separate memory controllers 26 and 36, which is a source of extra complexity and hence leads to higher productions costs. Additionally, two separate RAM banks 16 and 18 are used, which adds additional components to the DVD player 10, and thus additional expense